What is ASTM D2240?

The ASTM D2240 standard is used to evaluate the hardness of a rubber sample with the use of a series of tests performed with a durometer. Hardness is measured when a force is applied to the sample with an indentor under specific conditions.

What Shore hardness test?

Shore hardness is a measure of the resistance of a material to penetration of a spring loaded needle-like indenter. Hardness of Polymers (rubbers, plastics) is usually measured by Shore scales. Shore A scale is used for testing soft Elastomers (rubbers) and other soft polymers.

How is durometer calculated?

The principle used to measure hardness is based on measuring the resistance force of the penetration of a pin into the test material under a known spring load. The amount of penetration (max. 2.5 mm) is converted to hardness reading on a scale with 100 units.

What is ASTM D2000?

ASTM D2000 is an industry specification that provides buyers and suppliers with a standard way to describe rubber. Published by ASTM International and designed for automotive applications, this classification system is used by many other industries because it’s clear, concise, and highly descriptive.

What is BHN in steel?

Brinell steel hardness test The acronym BHN is used to show a Brinell Hardness Number. The term ‘Brinelling’ has come to mean the permanent indentation of any hard surface. The test involves a large, heavy ball, which is pushed against steel at a predetermined level of force.

Is Shore A harder than Shore D?

The higher the number on the scale, the harder the material. The major differentiation between the Shore A and Shore D is that Shore A is specified to measure flexible rubbers while Shore D is specified for harder, rigid materials. However, the ranges do tend to overlap at higher levels.

What does 70 Shore A mean?

The hardness of rubber compounds is measured by the Shore A durometer; the higher the durometer, the harder the compound. 70-durometer hardness should be used whenever possible as it offers the best combination of properties for most O-Rings applications.

Is a higher durometer harder?

Durometer is a gauge that can be used to check the hardness of given materials. Hardness is the resistance to surface penetration. Lower numbers indicate softer, more flexible materials, while higher numbers indicate harder and typically more durable materials.

How do you read ASTM?

Every ASTM standard is identified by a unique designation. It includes a capital letter (A – H), followed by a serial number ranging from one to four digits, a dash, and finally the year of issue.

How does the ASTM D2240 shore hardness test work?

Micom offers ASTM D2240 shore hardness testing as part of its plastics testing services. ASTM D2240 allows for a measurement of the initial hardness, or the indentation hardness, after a given period of time. The test requires applying the force in a consistent manner, without shock, and measuring the hardness.

How is the ASTM D2240 hardness related to the Young’s modulus?

Using linear elastic indentation hardness, a relation between the ASTM D2240 hardness and the Young’s modulus for elastomers has been derived by Gent and by Mix and Alan Jeffrey Giacomin. Gent’s relation has the form {\\displaystyle S} is the ASTM D2240 type A hardness. {\\displaystyle S<40} .

What do you need to know about the Shore durometer?

The basic test requires applying the force in a consistent manner, without shock, and measuring the hardness (depth of the indentation). If a timed hardness is desired, force is applied for the required time and then read. The material under test should be a minimum of 6 mm (0.25 inches) thick.

How big is a shore hardness test specimen?

The test specimens are generally 6.4mm (¼ in) thick. It is possible to pile several specimens to achieve the 6.4mm thickness, but one specimen is preferred. The hardness numbers are derived from a scale. Shore A and Shore D hardness scales are common, with the A scale being used for softer and the D scale being used for harder materials.